This invention relates to an inching control system for an industrial vehicle.
The conventional inching control system operates to disconnect the vehicle clutch when the brake pedal is depressed, thereby enabling an inching or step-wise advance under the control of a single pedal whereby, for example, a fork lift truck can gradually and safely approach a shipping pallet or a loading/unloading platform.
If the inching system disconnects the clutch immediately upon the depression of the brake pedal, however, then the stopped vehicle does not start up again the instant the brake pedal is released. That is, there is a time delay between the release of the brake pedal and the reengagement of the clutch. Accordingly, if the vehicle is on a ramp of incline, it coasts backward to some extent before its forward motion is resumed. In order to prevent such dangerous backsliding, two brake pedals are often provided. One controls the inching system; the other is independent of the inching system, and the two brake pedals are separately depressed and controlled by the operator. Such a dual brake system arrangement is different to operate, however, and its construction is both costly and intricate.
Examples of various types of prior art systems are disclosed in U.S. Pats. Nos. 2,872,000; 2,917,143; 3,181,667; 3,292,752; 3,313,383, 3,631,948 and 3,705,643.